A 19-year-old college student suspected of murdering his parents and attempting to shoot dead two of his younger siblings had planned the attack over a 'long period of time', prosecutors said Monday.

Ashton Sachs appeared in court for the first time to face charges of murder after his parents Andra, 54, and Bradford Sachs, 57, were found shot in their sleep at their 3.5million home in San Juan Capistrano, California.

Prosecutors allege that Sachs set out to kill everyone inside the 9,000-square-foot mansion, down to his 8-year-old adopted little brother.

Killer son: Ashton Sachs was arrested last week on suspicion of shooting his parents Bradford and Andra Sachs in their sleep on February 9

Charges: Sachs could face the death penalty if convicted of murdering his parents (Bradford on the left, Andra on the right). He is also facing charges for the attempted murder of his siblings

Someone had a key: There was no sign of forced entry at the family's $3.5million home in San Juan Capistrano the night of the attack

Sachs is also facing two counts of attempted murder for shooting at his younger brother and sister, paralyzing the boy and missing the 17-year-old girl. Sachs has another teenage sister who was also uninjured in the attack.

'This was not something that happened at the spur of the moment or in the heat of passion,' prosecutor Ebrahim Baytieh said.

'This is a horrendous crime involving an adult man who decided to murder and kill the people who loved him the most, and the people who were supporting him,' Baytieh added.

At the time of the murders, Sachs had moved out of the family home to Seattle, Washington where he was attending school.

Tension? Sachs had moved out of the family home and had been living in Seattle attending college. Pictured above on his Facebook profile

Sachs drove the 1,200 miles from his home in Seattle to Southern California and snuck into the family home sometime after midnight on February 9.

He first shot dead his parents while their were sleeping in their bed with a firearm he purchased himself.

From there, Sachs targeted his younger siblings. He shot and hit his 8-year-old brother and missed hitting his 17-year-old sister before fleeing the property and taking a flight back to Seattle.

Baytieh wouldn't elaborate on a motive for the crime, but did say money wasn't a factor - though his parents were quite wealthy.

The couple (both pictured on the right) separated in 1999, but continued living and running several businesses together

'I don’t have any indication whatsoever that his parents were anything other than supporting parents who cared about their children, all of their children — who supported their children, all of their children,' Baytieh said.

Sachs wasn't arrested until March 6, since neither of his siblings could identify the shooter.

Authorities first investigated whether one of the Sachs' many business connections was responsible, since they found several people who 'did not like' the couple.

The investigation narrowed in on Ashton Sachs when he filed for guardianship of his younger siblings along with older brother Myles, who was away at school during the attack.

New parents: A few weeks after their parents' murders, Ashton filed for guardianship of his three younger siblings along with older brother Myles, who was away at school at the time of the shootings. The brothers are pictured together in Ashton's Facebook profile picture on the left, while Myles is pictured by himself on the right

In court on Monday, the judge delayed Sachs' arraignment until April 4. Until then, he will be held without bond at the Central Men's Jail in Orange County.

If convicted, Sachs could face the death penalty.

The Sachs divorced nearly 15 years ago, but continued to live and raise their five children together, despite a separation marked with restraining orders and hostility.

Following their divorce, which had been characterized by Andra Sachs as a 'financial decision,' according to a friend, the couple adopted a boy and girl from Russia.